March 31, 1946 oil was trading @ $1.37 per barrel.
OPEC was formed in 1960 with five founding members: Iran, Iraq, Kuwait, Saudi Arabia and Venezuela and the price of oil was trading @ $3.00 per barrel.
In March of 1971, the balance of power to control crude oil prices shifted from Texas, Oklahoma and Louisiana to OPEC. By the end of 1971 six other nations had joined OPEC: Qatar, Indonesia, Libya, United Arab Emirates, Alageria and Nigeria, oil was trading @ $3.60 per barrel.
The Yom Kippur War started with an attack on Israel by Syria and Egypt on October 5, 1973. The US and many other countries showed support to Israel. As a result Arab exporting nations imposed an embargo on the nations supporting Israel, still known as the Arab Oil Embargo here in the United States. Oil was trading @ $4.20 per barrel.
Beginning in the 1980s the US became more energy efficient with better insulation of homes, energy efficiency in industrial processes, and automobiles with higher gas mileage and oil was trading @ $6.34 per barrel.
Events in Iran and Iraq led to another round of crude oil price increases in 1979 and 1980. The Iranian revolution resulted in the loss of 2 to 2.5 million barrels of oil per day between November of 1978 and June of 1979. In 1980 Iraq's crude oil production fell 2.7MMBPD and Iran's production by 600,000 barrels per day during the Iran/Iraq War. The combination of these two events resulted in crude oil prices more than doubling from $14 in 1978 to $35 per barrel in 1981, oil was trading @ $6.94 per barrel.
From 1982 to 1985 OPEC attempted to set production quotas low enough to stabilze prices. Repeated failures occured because various members of OPEC would produce beyond their quotas. Saudi Arabia acted as the swing producer cutting its production to stem the free falling prices. In August of 1985 they tired of this role and linked their oil prices to the spot market and in early 1986 increased production from 2 MMBPD to 5 MMBPD and oil was trading at $26.00 per barrel
As of today December 12, 2014 oil is trading at $57.49 per barrel.